Process of making plates for printing or embossing.



` J. HARTNB JB., PROCESS 0F MAKING PLATES P0 INTING 0R. EMBUSSING.

' .APPLILGATION FILED MAB.5, 1907.

921,397w Patented May 11, 1909.

UNITED sTATEs rATiiNT caricia JOHN HARTNETT, JR., OF WEST ARLINGTON, MARYLAND, ASSIGNOR TO HARTNETT VUL- OOGRAPH COMPANYl OF BALTIMORE CITY, OF BALTIMORE, MARYLAND, A CORPORATION OF MARYLAND.

PROCESS F MAKNG PLATES FOR PRINTING OR EMBOSSING.

No. 921,397. Speccation of Letters Patent. Patented May 1 1, 1909.

i Application filed March 5, 1907. Serial No. 360,639.

To all whom it may concern.' of the film exposed to it more or less in- 55 Be it known that I, JOHN HARTNETT, Jr., soluble, depending upon the amount of light a. citizen of the United States, and resident passing through the transparency. The

of `West Arlington, county of Baltimore, film exposed to clear portions of the trans- 5 State of Maryland, have invented certain parency will be quite insoluble, while the new and useful Improvements in Processes film exposed to shaded portions will be more 60 of Making Plates for Printing o1' Emboss or less soluble according to the amount of ing, of which the following is a specificalight received through them. After sulfitioin. cient exposure the plates are separated The object of this invention is to produce and the sensitized plate is placed in a bath relief plates suitable for printing, embossof any suitable solvent of rubber and sub- 65 ing and other purposes. jected to the bath until the parts which were The invention is based on the fact that shaded by the transparency have swelled to pure crude rubber under certain conditions the desired relief. The amount of swelling f..

is sensitive to light and is rendered more or relief at any particular pointI will depend or less insoluble by exposure to light and upon the thickness of the film, the amount 70 that this property of rubber is increased or of light to which it has been subjected, and intensified by the admixture of a small perthe length of time the developing process routage of asphaltum or coal tar. has continued. When the desired relief has '20 In practicingl the invention a solution is 'been securedthe plate is removed from the pre pared consisting of pure crude rubber bath and a plaster cast made from it,'which 75 dissolved in any suitable-solvent ofrubber cast will be found to have the outline and and to this solution is added asmall pery more or less of the relief of the subject from centage of asphaltum or coal tar. This sowhich the negative was made. If it be delution is prepared and handled in a dark sired to make an electrotype this plaster cast room and is used to sensitize plates which is dipped in boiling' oii (such as linseed oil 80 should also be protected from light until or paraffin) to fill the pores and then coated used. A plate is coated with one or more* with graphite after which an electrotype lilins of the above solution according to may be made in the usual manner and the amount of relief desired, the films bestereotype plates may also be made.

ing thoroughly dried before subjecting Stereotype plates, positive and negative. them to use. It is found that by thormade as above described, may be used for oughly drying the films they are rendered embossing. For light embossing', such as is more sensitive. The effect of light, either required to bring out the features of photo- 35 natural or artificial upon a plate prepared graphs, the plaster cast above described, to-

as above to render the exposed parts of gether with a negative cast made from the 90 the lin more or less insoluble, depending positive, may be used as a pair of embossing upon the au'ieunt of light and the thickness dies. Such dies will exactly register with of the film. the features of a photograph produced 40 A transparency is made of the object to from the original negative and they may be 'be reproduced in relief. This transparency used to emboss pictures printed from the 95 may be a photographic negative or positive negative.

on glass, or any similar 'translucent repre- The iiivent-ion is illustrated in the accomseiitation of the object, a photographic negapanying drawing in which, tive being usually preferred. This 'trans- I `igure l is a sectional view of a plate senpai'e cy is placed face to face with the film sitized with a film of rubber; Fig. 2 is a sec 100 of the sensitized plate, the two being clamped tional view of a pan containing the plate together in a frame as in the ordinary after exposure and a solvent or developing method of printing photographs. The tiuid; Fig. 3 is a sectional view of the plate transparency is then-exposed to light, either after development and a plaster cast made natural or artificial, for a suitable time, del from the plate; Fig. Ll; is a sectional view of pending' upon the intensity of the light, the two complementary plaster casts. density of the negative and the thickness of .Referring 'to the drawing, l indicates the the film. rlhe light will render the parts plate and 2 the Vlilin before development.

In Fig. 2, 3 indicates the pan, et the developing fluid or solvent and 2a the film after treatment by the fluid.

In Fig. 3, 5 indicates a negative plaster cast taken from the surface 2, and in Fig. 4, 6 indicates a positive plaster cast made from the cast 5, the two being complementary.

It will be evident that my improved process is capable of many uses in the arts. rl'hus printing plates for reproducing pictures or typographie matter can be produced as well as embossing dies, the process being, in general, applicable to the production of relief plates for any purpose.

Having described my invention what I claim and desire to secure by Letters-Patent 1. A method of reproducing an object in relief which consists in seusitizing a plate with a film of pure rubber having a small percentage of asphaltum or coal tar incorporated therewith, exposing said film to light passing through a transparency of the object to be reproduced and then treating said film with a solvent of rubber until the desired relief is obtained.

2. A method of reproducing an object in relief which consists in coating a suitable plate with a film of pure rubber dissolved in a suitable solvent and having a small percentage of asphaltum or coal tar incorporated therewith, exposing said film to light passing through a transparency of the object to be reproduced, and then treating desired relief is obtained, and making a plaster cast from the said rubber relieffi plate.

Je. A method of making dies for reproducing an object in relief which consists in dissolving pure rubber in a suitable solvent and adding a small percentage of asphaltum o1' coal tar, then sensitizing a plate by coating it with one or more films of said rubber solution, then exposing said film to light passing through a transparency of the object to be reproduced, then treating said film with a solvent of rubber' until the desired relief is obtained, then making a plaster cast of the said rubber film, and then making complementary dies from the said plaster cast in any suitable manner.

In testimony whereof I afHXV my signature in presence of two witnesses.

JOHN HARTNETT, JR.

Witnesses:

VVILLLAM B. EHLEN, JAs. S. GosNELL, Jr. 

